Plug switch



B. LENDER PLUG SWITCH Sept; 5., 1939' INVENTOR. B @156 Linda! ATTORNEYS Filed April 2, 1938 Patented Sept. 5, 1939 UNITED STATES PATENT OFFICE PLUG SWITCH Application April 2, 1938, Serial No. 199,547

3 Claims.

This invention relates to a switch adapted to be encased within the ordinary electric plug in common use in connection with such structures as electric irons.

Particularly the invention relates to a switch which is automatically operable upon movement of an electrical device such as an electric iron to operating and non-operating positions, to supply current to the device or to out off the flow of current to the device.

In addition, means are provided whereby the automatic functioning of the device may be eliminated and manual control of the energizing current may be effected.

It is an object of the invention to provide an electric plug having an automatic switch integral therewith.

It is a further object of the invention to provide such a plug having, in addition, manual means whereby the automatic functioning of the switch may be eliminated and the control exerted entirely at the will of the operator.

Further objects and features of the invention will appear when the following specification is considered in connection with the appended drawing, in which Figure 1 is a front elevation. of the plug switch of the invention showing particularly the manual arrangement for causing the current to be turned on and off.

Figure 2 is a side elevation of the device of Figure 1.

Figure 3 is an elevation, similar to Figure 1, but with one half of the housing removed so that the internal construction is apparent. This figure shows the switch operated by the manual means to such position that current may flow through the device to which the plug is connected.

Figure 4 is a fragmentary elevational View similar to Figure 3 but showing the position of the parts when the manual control device is in position to permit automatic operation of the switch.

Figure 5 is a view similar to Figures 3 and 4 showing the position. of the parts when the manual control device is operated to cause the circuit to be broken.

The switch of this invention is enclosed in a housing of common form comprising two mating parts l0 and II (Figures 1 and 2) within which the major portion of the mechanism is enclosed. Fastened to the element H! of the housing are the two prong receiving members I2 and I3 which are adapted to cooperate with upstanding prongs within a plug casing of the type which is usual in the structure of electric irons.

These prong receiving members may be fastened to the housing in any suitable manner. In the particular instance this fastening is through the medium of screws which pass through the members and thread into inserts molded in the housing. The member l3 has extending upwardly therefrom a conducting strip I4 which is fastened in the casing by being held under the member l3 and having the screw which passes through the member [3 likewise pass through a hole therein. At its upper end the strip I4 is provided with a screw hole in which terminal screw [5 is inserted, this screw serving to hold the conductor l6 of the cord H in position. The cord I 1 passes through a hole, half of which is formed in each of the housing members lo and I l in the usual manner, and is surrounded by a protecting spring 18 as is common in plug con-- struction.

The wire [9 of the pair of wires in the cord I! is fastened beneath a screw 20 which is threaded into a conducting strip 2| which strip extends downwardly and to the left and is held in position by means of a pin 23 extending through the member into an insert in the casing I0.

Pivoted on the pin 23 is the switch arm 22 which as is readily seen by reference to Figures 3, 4 and 5 is of L-shape and extends to the right and downwardly so that it may make contact with the prong receiving member I 2 at the upper end of that member.

It will be seen that when the iron or other device on which this plug is used is in operative position, gravity will cause the switch member 22 to move clockwise about the pivot 23 so that the circuit is completed to the member l2, but that when the iron is moved to an inoperative position, as for example by placing it on the heel stand, the plug is in such position that gravity acts in the opposite direction and causes the arm 22 to rotate counterclockwise about the pivot, breaking the circuit.

It will be obvious that at times the switch arm must be caused to be held in either its circuit closing or circuit opening position. For example, it may be desired to have the iron heating, while resting on its heel stand or, conversely, it may be desirable to have the current shut off while the iron is in actual use, in order that it may not attain too high a degree of heat.

In order to provide for such conditions, a manual switch control element is made a part of the present structure. The manual control includes a shaft 25 which extends through the housing member I and on which there is fastened exterior of the housing a switch knob 21 cooperating with a dial marked on the exterior of the housing so that a pointer on the knob will indicate the on and off positions as well as the intermediate position in which the switch operation is automatic.

At its inner end shaft 25 carries an arm 26, which arm overlies switch arm 22 and is adapted to cooperate with a pin 24 extending upwardly from that arm. When knob 27 and shaft 25 are rotated in a clockwise direction (as seen in Figure 3) the cooperation of arm 26 and pin 24 will cause arm 22 to likewise rotate in a clockwise direction and to complete the electric circuit to member I2. This is the condition shown in Figure 3.

When the control knob 27 is moved to a position intermediate between those marked on and off in'Figure 1, the arm 26 will lie as shown in Figure 4 and the switch arm 22 will then be under the influence of gravity, as described above, to cause automatic making and breaking of the circuit. When the knob 2'! is rotated to the ofi position, pin 26 will occupy the position of Figure 5, that is, it will have been rotated 180 from the position shown in Figure 3 and will then hold the arm in position (Figure causing the circuit to be broken. A comparison of Figures 3 and 5 will illustrate how this is caused by rotation of the knob, since it will be seen that the arm 26 is in contact with pin 24 on one side or the other, depending upon the position of the knob 21 and shaft 25.

As is usual in plugs of the type here considered, strengthening projections 28 and 29 are provided, together with similar strengthening projections in the mating portion of the housing. These projections are provided with holes through which bolts 39 may be inserted, these bolts serving to hold the two housing members together, since the bolts cooperate with nuts on the opposite side of the assembled housing or thread into inserts molded in the housing as the case may be.

As will be readily seen from the above, when the switch of this invention is applied to an electric iron, the iron may be supplied with current at all times by manipulating the switch knob 21 so that it is in the on position as shown in Figure 1. Again the iron may be permanently disconnected from the circuit by moving the switch knob 21 to the off position. By moving the switch to a position intermediate on and off positions, the switch arm 22 will be freed for movethat this heat control is effective to turn the current off automatically when the iron is not in use and on again automatically when the iron is ac- 7 tually in use. Moreover, the heat control unit is outside the casing of the iron where it is not subject to extreme temperatures and where any damage which may occur may be readily repaired.

While the invention has been described as having a switch arm cooperating with one terminal and one prong receiving member only, it will be seen that the construction might easily be altered to provide a similar switch arm for the other terminal and for the other prong member.

Although a preferred embodiment of the invention has been described, it is to be understood that the scope of the invention is not limited by the foregoing specification, but solely by the appended claims.

What I claim is:

1. In a switching device housed in a cord plug, the combination of a switch arm pivoted in position to make and break the circuit through the plug in accordance with the plug position and manually operative means to hold said arm in circuit closing or circuit opening position irrespective of the plug position. 7

2. In a switching device housed in a cord plug the combination of a switch arm pivoted in position to make and break the circuit through the plug in accordance with the plug position and manually operated means to hold said arm in circuit closing or circuit opening position irrespective of the plug position, said means comprising a pin on said switch arm, a cooperating arm rotatable about an axis with a shaft extending through the housing and a knob mounted on said shaft exterior of said housing. a

3. In a device of the class described, in combination, a housing element, a pair of prong receiving members fastened to said element atone end thereof, a conductor strip extending upward from one of said members and provided with means for fastening a power supply conductor thereto, a second conductor strip extending upwardly from a point above and between said members and provided with means for fastening a supply con ductor thereto, said second conductor strip being fixed to said housing at its lower end by means of a pin, a switch arm pivoted on said pin and elecertically connected to said conductor strip thereby, said arm being L-shaped, one leg of said L extending downwardly and being positionable against the upper surface of the second prong receiving member, said switch arm being adapted to rotate about its pivot in accordance with the position of the device whereby the power supply circuit is automatically extended to said prong receiving members in predetermined position of the device, and means to manually operate said switch arm, said means being movable to a plu-' rality of positions in one of which it causes the switch arm to move to circuit extending position irrespective of the position of the device, in another of which it' causes the switch arm to move to circuit opening position irrespective of the position of the device, and in the third of which it permits free movementof the switch arm in accordance with the position of the device.

BETTY LINDERL 

